Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/12—Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/07—Flat, e.g. panels
  • B29C48/08—Flat, e.g. panels flexible, e.g. films
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
  • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
  • B29C55/023—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets using multilayered plates or sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
  • B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B38/00—Ancillary operations in connection with laminating processes
  • B32B38/0032—Ancillary operations in connection with laminating processes increasing porosity
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
  • B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
  • B32B5/022—Non-woven fabric
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
  • B29K2105/04—Condition, form or state of moulded material or of the material to be shaped cellular or porous
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
  • B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
  • B29K2105/16—Fillers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/724—Permeability to gases, adsorption
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2323/00—Polyalkenes
  • B32B2323/04—Polyethylene
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
  • Y10T442/674—Nonwoven fabric with a preformed polymeric film or sheet
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
  • Y10T442/68—Melt-blown nonwoven fabric

Definitions

• This invention is related to a breathable multi-ply barrier film and a breathable barrier film laminate comprising said breathable multi-ply barrier film and a nonwoven web.
• the laminate is particularly useful as an outer cover for disposable diapers and other disposable personal care products, and for breathable surgical gowns, surgical drapes, coveralls, and other breathable protective apparel.
• this invention is directed to a method for producing the breathable multi-ply barrier film and laminate.
• the present invention is directed to breathable barrier films and laminates of breathable barrier films and nonwoven materials.
• Such laminates have a wide variety of uses, particularly in the areas of limited use and disposable items.
• Films have been traditionally used to provide barrier properties in limited use or disposable items.
• limited use or disposable I mean that the product and/or component is used only a small number of times, or possibly only once, before being discarded.
• examples of such products include, but are not limited to, surgical and healthcare related products such as surgical drapes and gowns, disposable work wear such as coveralls and lab coats, and personal care absorbent products such as diapers, training pants, incontinence garments, sanitary napkins, bandages, wipes and the like.
• films are used to prevent cross exchange of microorganisms between the wearer and the patient.
• these films are generally effective barriers with respect to water vapor and the like, they are not aesthetically pleasing because their surfaces are smooth and either feel slick or tacky, and they are visually unappealing, making them less desirable in apparel applications and other uses where they are in contact with human skin.
• garment-like isolation gowns for use in hospital environments most likely would increase the comfort of the wearer while reducing the apprehensiveness of the patient.
• a primary purpose of the film in such laminates is to provide barrier properties.
• such laminates be breathable so that they can transmit water vapor which, in turn, requires that the film be breathable.
• Apparel made from laminates of breathable or microporous films are more comfortable to wear because they reduce the water vapor concentration and the consequent skin hydration underneath the apparel item.
• Breathable films and a method for producing such films are taught, for example, by U.S. Patent 3,844,865; and breathable laminates employing porous films and nonwoven materials are taught by U.S. Patent 5,560,974 and U.S. Patent 5,169,712.
• suitable barrier film laminates In order to be suitable for use in surgical garment applications, as well as other protective apparel, suitable barrier film laminates must meet the requirements of ASTM Standard F-1670 and ASTM Standard F-1671, which standard test methods provide a basis for assessing the effectiveness of materials used in protective clothing for protecting the wearer against contact with body fluids that potentially contain blood-borne pathogens.
• Conventional film laminates comprise a single layer of microporous film and, as such, defects and/or microscopic holes in the film layer caused by film imperfections frequently cause failure of the laminate to satisfy the requirements of ASTM barrier performance.
• a method for producing a moisture vapor permeable multi-ply film in which a polymer suitable for use as a polymeric film and comprising a filler having a particle size suitable for pore formation is extruded to form an extruded film.
• the extruded film is hot blown, resulting in formation of a hot blown film bubble.
• the hot blown film bubble is collapsed and trimmed, forming a multilayer film, after which the multilayer film is stretched, forming a plurality of micropores in both layers of the multilayer film.
• the stretched, microporous, multilayer film is bonded to a nonwoven web layer, forming a nonwoven/film laminate.
• the barrier film of this invention is a multilayer film, the probability of an imperfection in any one area of one layer of the film aligning with an imperfection in the other layer of the film is greatly reduced or eliminated, thereby substantially increasing the probability that the material produced in accordance with the method of this invention will meet ASTM test requirements.
• the multilayer film is stretched to a length in the range of about 350 to 500% of its initial length.
• the resulting film has a water vapor transmission rate (WVTR) in the range of about 1200 grams per square meter per 24 hours (g/m 2 /24 hours) (measured by ASTM Standard Test E96-80 with CELGARD ® 2500 as control).
• WVTR water vapor transmission rate
• Laminates of this invention have a wide variety of uses including, but not limited to, items such as surgical drapes and gowns, as well as various articles of clothing, either the entire article or simply as a component thereof.
• Fig. 1 is a schematic diagram of a hot blown process for producing a multi-ply film
• Fig. 2 is a schematic diagram of a process for producing a breathable barrier film laminate in accordance with one embodiment of this invention.
• Fig. 3 is a cross-sectional view of a laminate of this invention.
• breathable refers to a film or laminate having a water vapor transmission rate (WVTR) of at least about 300 g/m 2 /24 hours measured using ASTM Standard E96-80, upright cup method, with minor variations as described in the Test Procedure below.
• WVTR water vapor transmission rate
• nonwoven web means a web that has a structure of individual fibers or threads which .are interlaid, but not in an identifiable, repeating manner.
• Nonwoven webs have been, in the past, formed by a variety of processes such as, for example, meltblowing processes, spunbonding processes, and bonded carded web processes.
• spunbonded fibers refers to small diameter fibers which .are formed by extruding a molten thermoplastic material as filaments from a plurality of fine, usually circular, capillaries of a spinnerette with the diameter of the extruded filaments then being rapidly reduced as by, for example, eductive drawing or well-known spunbonding mechanisms.
• spunbond web refers to a nonwoven web of spunbonded fibers.
• Methods for producing spunbond webs are taught, for example, by U.S. Patent 3,802,817 to Matsuki et al., U.S. Patent 4,340,563 to Appel et al, and U.S. Patent 5,382,400 to Pike et al., all of which are incorporated herein by reference.
• polymer generally includes, but is not limited to, homopolymers, copolymers, such as for example, block, graft, random and alternating copolymers, terpolymers, etc., and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term “polymer” includes all possible geometric configurations of the material. These configurations include, but are not limited to, isotactic, syndiotactic, and random symmetries.
• the term "consisting essentially of does not exclude the presence of additional materials which do not significantly affect the desired characteristics of a given composition or product.
• Exemplary materials of this sort would include, without limitation, pigments, antioxidants, stabilizers, surfactants, waxes, flow promoters, solvents, particulates, and materials added to enhance processability of the composition.
• a measure of the breathability of a fabric is the water vapor transmission rate (WVTR) which, for sample materials, is calculated essentially in accordance with ASTM Standard E96-80 with minor variations in test procedure as set forth hereinbelow. Circular samples measuring 3 inches in diameter are cut from each of the test materials, and tested along with a control, which is a piece of CELGARD ® 2500 sheet from Celanese Separation Products of Charlotte, North Carolina. CELGARD ® 2500 sheet is a microporous polypropylene sheet. Three samples are prepared for each material. The test dish is a No. 60- 1 Vapometer pan distributed by Thwing-Albert Instrument Company of Philadelphia, Pennsylvania.
• each Vapometer pan 100 milliliters of water is poured into each Vapometer pan and individual samples of the test materials and control material are placed across the open tops of the individual pans. Screw-on flanges are tightened to form a seal along the edges of the pan, leaving the associated test material or control material exposed to the ambient atmosphere over a 6.5 cm diameter circle having an exposed area of approximately 33.17 cm 2 .
• the pans are placed in a forced air oven at 100°F (32°C) for one hour to equilibrate.
• the oven is a constant temperature oven with external air circulating through it to prevent water vapor accumulation inside.
• a suitable forced air oven is, for example, a Blue MP Power-O-Matic 600 oven distributed by Blue ME Electric Company of Blue Island, Illinois.
• Test WVTR (grams weight loss over 24 hours) x 315.5 g/m 2 /24 hours.
• the relative humidity within the oven is not specifically controlled.
• the WVTR for the CELGARD ® 2500 control has been defined to be 5000 g/m 2 for 24 hours. Accordingly, the control sample was run with each test and the preliminary test values were corrected to set conditions using the following equation:
• WVTR (Test WVTR/control WVTR) x (5000 g/m 2 /24 hours) DESCRIPTION OF PREFERRED EMBODIMENTS
• This invention is directed to breathable barrier films and to soft, breathable barrier film laminates employing said films. This invention is also related to a method for producing said breathable barrier films and breathable barrier film laminates.
• the breathable barrier film of this invention is a moisture vapor permeable multi-ply film produced from a polymer suitable for use as a polymeric film, which polymer is loaded with a filler, preferably an inorganic filler.
• Preferred polymers suitable for use in this invention are polymers which produce non-elastic films. Such polymers include, but are not limited to, Catalloy available from Himont, Wilmington, Delaware, flexible polyolefms available from Huntsm.an Chemical Corporation, Odessa, Texas, random copolymers, linear low density polyethylene, and mixtures thereof.
• the film layer also comprises a filler which enables development of micropores during stretching of the film.
• a filler means particulates and other forms of materials which can be added to the polymer and which will not chemically interfere with or adversely affect the extruded film, but which is able to be uniformly dispersed throughout the film.
• the fillers will be in particulate form and usually will have somewhat of a spherical shape with average particle sizes in the range of about 0.50 to about 8 microns.
• the film will usually contain in the range of about 10 to 50 volume percent filler based upon the total volume of the film layer.
• the film comprises in the range of about 35%> to 40%> by volume of said filler material.
• organic and inorganic fillers are suitable for use in this invention provided that they do not interfere with the film formation process, the breathability of the resultant film, or its ability to bond to another layer, such as a fibrous polyolefm nonwoven web.
• suitable fillers include calcium carbonate (CaC0 3 ), various kinds of clay, silica (Si0 2 ), alumina, barium sulfate, sodium carbonate, talc, magnesium sulfate, titanium dioxide, zeolites, aluminum sulfate, cellulose-type powders, diatomaceous earth, magnesium carbonate, barium carbonate, kaolin, mica, carbon, calcium oxide, magnesium oxide, aluminum hydroxide, pulp powder, wood powder, cellulose derivatives, polymer particles, chitin and chitin derivatives.
• the breathable barrier film of this invention is a moisture vapor permeable multi-ply film.
• This moisture vapor permeable multi-ply film is produced by extruding a polymer comprising a filler having a particle size suitable for pore formation. Average particle size of the filler is preferably in the range of about 0.5 microns to about 8.0 microns and more preferably in the range of about 0J microns to 1.0 microns.
• the extruded film is hot blown so as to form a hot blown film bubble.
• the hot blown film bubble is then collapsed and the edges trimmed, forming a multilayer film.
• the multilayer film is then stretched, resulting in formation of a plurality of micropores in the multilayer film.
• the multi-ply film breathable in order to make the multi-ply film breathable, it is preferably loaded with calcium carbonate particles and stretched in the range of about 3.5 to about 5.0 times its initial length once in the machine direction to make it microporous.
• the typical gauge of each ply of pre-stretched film is 1.5 mil.
• the multi-ply film preferably has a total film gauge of about 0.8 mils.
• the stretched multilayer film preferably has a WVTR in the range of about 1200 g/m 2 /24 hours to about 4500 g/m 2 /24 hours.
• the particle size of the filler material is such that upon stretching of the polymeric film, micropores having an average pore size in a range of about 0.05 to about 0.06 microns are produced.
• the basis weight of the resulting stretched multi-ply film is preferably in the range of about 0.6 to 1.0 ounces per square yard (osy).
• the breathable barrier film of this invention is bonded to a nonwoven web material layer, forming a breathable barrier film laminate.
• a process for forming a breathable barrier film laminate in accordance with this invention is shown in Figs. 1 and 2.
• Multilayer filled film 11 is formed from a film extrusion apparatus 40, a blown unit, which includes an extruder 41 (See Fig. 1). From extruder 41, the filled polymeric material is introduced into the blown unit in which it is formed by air blowing through air ring 44 into bubble 47. Bubble 47 is then collapsed on collapsing frame 45 resulting in the formation of multilayer filled film 11.
• Multilayer filled film 11 is then trimmed by trimmer 46 after which it is wound onto windup 48 to produce a single roll of film which is multilayer.
• Multilayer filled film 11 is then unwound from film unwind 10 from which it is introduced into a film stretching unit 12, in particular a machine direction orienter, as shown in Fig. 2. Simultaneously therewith, a nonwoven web material layer 14 is unwound from continuous unwind apparatus 13 and applied to one surface of multilayer filled film 11 leaving film stretching unit 12.
• a second nonwoven web material layer 18 is unwound from a second continuous wind apparatus 17 and applied to the other surface of the stretched multilayer filled film 11 to form a nonwoven web/film/nonwoven web composite.
• the composite is then passed through bonding calender system 15 resulting in formation of the breathable barrier film laminate 20.
• Breathable barrier film laminate 20 is then wound onto surface winder 16.
• Breathable barrier film laminate 20 in accordance with one embodiment of this invention is shown in Fig. 3 and comprises breathable barrier film 24 sandwiched between nonwoven web material layers 23 and 25.
• the nonwoven material web layer of the breathable barrier film laminate is a spunbond material layer.
• other nonwoven materials may also be used as desired for a given application.
• the breathable barrier film laminate of this invention is particularly suitable for use in protective apparel including, but not limited to, surgical gowns, coveralls, surgical drapes, and the like.
• the material of this invention also meets the requirements of ASTM Standard F-1670 and ASTM Standard F-1671 regarding barrier requirements. While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Textile Engineering (AREA)
• Laminated Bodies (AREA)
• Professional, Industrial, Or Sporting Protective Garments (AREA)

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Applications Claiming Priority (4)

Publications (1)

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Citations (3)

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• 1998
  • 1998-12-11 US US09/210,323 patent/US6610163B1/en not_active Expired - Lifetime
  • 1998-12-16 GB GB0016471A patent/GB2348169B/en not_active Expired - Lifetime
  • 1998-12-16 WO PCT/US1998/026680 patent/WO1999030904A1/en active IP Right Grant
  • 1998-12-16 BR BR9813623A patent/BR9813623A/pt not_active IP Right Cessation
  • 1998-12-16 DE DE19882895T patent/DE19882895B3/de not_active Expired - Fee Related
  • 1998-12-16 AU AU19169/99A patent/AU1916999A/en not_active Abandoned
  • 1998-12-16 KR KR1020007006571A patent/KR100574736B1/ko not_active IP Right Cessation

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